As water balances are being calculated more precisely, the principles of reducing, reusing and recycling water are being adopted more strictly, as is the separation of clean from dirty water on mines.
Consulting engineering firm WSP environment and energy senior associate Karen King states that water balances are calculated by accounting for as much water use, storage, movement and discharge data as possible, which often means increasing the mine’s number of monitoring points.
“Instead of then calculating the water balance statically – using a spreadsheet and yearly or monthly time steps – water balances are modelled dynamically at daily time steps using software such as Goldsim,” King adds.
She points out that the General Notice 704 of the National Water Act assists in driving change from a water perspective, while the General Notice 267, promulgated in 2017, drives change from a water use licensing perspective.
General Notice 704 explains that a calculated exclusion zone needs to be determined around watercourses, and clean and dirty water needs to be separated. Thereafter, the dirty water needs to be stored in lined pollution control dams sized so that they do not spill more than once, on average, every 50 years. These changes have been successful, where implemented, as mining environmental impact assessments and water use licences will not be granted unless these measures are in place.
General Notice 267 has standardised the information required for water use licence applications across the provinces, which has made the process easier to follow and more transparent. It has also specified how long the various stages in the water use licence process must take. King notes that this has been successful in most provinces.
Meanwhile, mining companies are starting to use surfactants for dust suppression instead of water when affordable. However, using cleaner production techniques, environmental control technologies and process re-engineering can further reduce waste output of mines, King suggests.
From an air-quality perspective, the South African National Ambient Air Quality Standards and National Dust Control Regulations for dust fallout also assists in driving change.
The National Environmental Management: Air Quality Act 39 of 2004 (NEMAQA), which repealed the Atmospheric Pollution Prevention Act of 1965, came into effect on the September 11, 2005, initially with exclusions of certain sections such as the licensing of listed activities. The new Act introduces a system based on ambient air quality standards and corresponding emission limits to achieve these. Two significant regulations stemming from NEMAQA have been promulgated in this regard.
The draft National Dust Control Regulations have been released for public comment in General Notice 517 of 2018, with these coming into effect in November 2019. These regulations stipulate that the latest American Society for Testing and Materials method (2010) must be applied to dust fallout monitoring in South Africa.
King adds that it is important to note that these regulations differ between countries, as some are more advanced in terms of legislation than others.
She adds that solutions such as the replenishing of natural soils and grasses, cleaning of excess waste, proper waste removal and the replanting of trees can also sustain the environment for years when the mine is no longer operating.
The adoption of greener practices is often a significant money saver in the long term, with the adoption of greener practices also geared towards creating a large number of green jobs, reducing energy and material intensities during production, and significantly reducing greenhouse-gas emissions.
Financial stresses impact on companies’ ability to adopt greener practices. While such practices are often more affordable in the long term, they can be more expensive in the short term, and mining companies often do not have the funds available, particularly smaller companies.
King further elaborates that economic stresses also lead to labour stresses, impacting on mines, as they cannot develop with reduced staff numbers and while focussing on labour issues.
In terms of governmental assistance, legacy pollution issues, such as the acid mine drainage crisis, need be treated before time and money can be spent on new initiatives, she concludes.